1. Field of the Invention
The invention relates to an apparatus for handling of a disklike member, and an apparatus for optically inspecting a surface of a disklike member, and an end-effector means for holding a disklike member.
2. Description of Related Art
Apparatus for handling of a disklike member and for optically inspecting a surface of a disklike member, especially of wafer surfaces, are well known in the art.
Semiconductor wafers are produced by complicated multi-step processes in a clean room environment. The production of sophisticated electronic chips from wafers may include as many as about 150 steps. Technologies in the submicron range are very delicate, and there always exists a chance of error or malfunction at each of the many stages, which ought to be discerned as soon as possible. Inspection during the production process and at its end is an imperative stage of the production process and there exists a real need for effective inspection means, capable of inspecting a large number of wafers in an accurate manner within a reasonable time period.
To this end, in world-wide Semiconductor Fabrications, optical measurement tools are used for inspecting and analysing of defects on the wafer surface, which follows an optical characterisation and/or classification of the defects.
This analysis is done on the various measurement spot sizes with a microscope, which is called the Micro-Station, and also on larger areas on the wafer up to the whole wafer surface on the front and on the back side of the wafer. The measurement is carried out in a separate station which is called the Macro-Station. Within the Macro-Station the surface of the wafer is optically inspected by irradiating the surface with light. This kind of measurement is also referred to as Bright-Light-Inspection.
The Bright-Light-Inspection measurement on a wafer is done to check certain properties of the surface which can be made visible by shining light onto a surface of the wafer and looking to the reflected light at a certain angle. The color and the intensity under given angles between the wafer, the light source and an operator (in most cases the naked eye, seldom a camera) is giving the measurement results.
For that purpose, typically, the wafer will by positioned in a bright light beam and the surface of the wafer will be check with the naked eye, while the angle of the wafer surface is changed with respect to the eye and the light source. To be able to get all the required angles the wafer has to be rotated around two orthogonal axis's which are in plane with the wafer surface. FIG. 1 shows the respective co-ordination System of the wafer and the three degrees of rotation together with the rotating axis in-plane.
Today this measurement is done in a special set-up which is holding the wafer. This wafer holding mechanism incorporates the moving parts which are used to change the angle of the wafer surface to the light source. An example of such an holding mechanism is disclosed in JP-A 162133.
The major disadvantage of this kind of system is that it needs a special and quite complicated structural set-up in the Macro-Station which on the one side increases the costs of the Macro-Station and the footprint of it, and which in turn gives rise to higher maintenance costs in a quite expensive clean room environment. Moreover the handling expenditure increases since the handling robot has to place and pick the wafer to or from the holding mechanism. This is even more important if one takes into account that the Macro-station is often used in conjunction with a Micro-station. The additional handling decreases the throughput numbers of the system drastically.
These and other disadvantages have lead to the object of the present invention to provide an apparatus for handling of a disklike member or wafer, which avoids the described disadvantageous with respect to the handling and/or inspection of a wafer, which is simpler in design, has a reduced footprint, and an increase in throughput.